For separating and analyzing biogenic substances by using biological samples such as blood, high-performance liquid chromatographs (HPLC apparatuses) utilizing high-performance liquid chromatography (HPLC) have been widely used (for example, refer to Patent Document 1). As shown in FIG. 12, a general HPLC apparatus is configured in such a manner that, after a sample containing a biogenic substance is prepared in a sample preparation unit 90, the sample is introduced into an analysis column 91, and the biogenic substance is adsorbed on a packing material of the analysis column 91. The biogenic substance adsorbed on the packing material is eluted by supplying an eluent from an eluent bottle 93 to the analysis column 91 by using a liquid feed pump 92. The eluate from the analysis column 91 is introduced into a photometric mechanism 94, and by continuously measuring the absorbance of the eluate in the photometric mechanism 94, the analysis of the biogenic substance is carried out.
In an HPLC apparatus 9, in order to stably carry out analysis of a biogenic substance, a deaerator 95 is installed at the upstream of the liquid feed pump 92 (for example, refer to Patent Document 2). The deaerator 95 is provided so as to remove gas, such as oxygen, remaining in the eluent. The installation of the deaerator 95 into the HPLC apparatus 9 prevents formation of air bubbles from gas dissolved in the eluent, can prevent destablization of the feed rate of the liquid feed pump 92, and therefore enables the analysis of a biogenic substance in the HPLC apparatus 9 to be stably carried out.
As shown in FIG. 13, an example of a deaerator 95 is configured so as to suction and remove the dissolved gas in the eluent by passing the eluent through a gas permeable tube 97 disposed in a reduced-pressure space 96 and reducing the pressure of the reduced-pressure space 96 using a pump 98 (for example, refer to Patent Document 3). In other words, when the eluent passes through the inside of the gas permeable tube 97, the dissolved gas in the eluent is transferred to the outside of the gas permeable tube 97 (the reduced-pressure space 96), thereby being removed.
The deaerator 95 having such a configuration is also used for prevention of oxidation or prevention of development of microorganisms in manufacturing processes of food, drinking water or the like, as well as in the HPLC apparatus 9 shown in FIG. 12.    Patent Document 1 Japanese Patent Application Laid-Open No. 7-120447    Patent Document 2 Japanese Patent Application Laid-Open No. 2001-133445    Patent Document 3 Japanese Patent Application Laid-Open No. 2000-275229